The retention of semen samples plays a decisive role in the diagnosis of infertility, and correctly instructing the examinee to collect semen is the most important and basic work in the experimental diagnosis of male infertility. Specific details are as follows: (1) Abstinence must be 3-5 days before semen examination (i.e., no more ejaculation for 3-5 days after the last semen discharge, semen specimen within this period of time is suitable for semen examination). Too short (<3 days) or too long (>5 days) a period of abstinence is not suitable for semen examination. (2) It is required that semen be collected by masturbation and not retained by condom or interrupted intercourse. Particular attention should be paid to the fact that the ejaculation process should be thorough, i.e., the semen should be ejaculated as completely as possible from the body. If the ejaculation is not sufficiently fluid (sexual arousal is not high enough), the amount of semen retained will be less than the actual semen volume. If the semen volume is not close to the real level of the examiner, it will seriously affect the accuracy of the test results. (3) The semen specimen should be collected in its entirety in the designated container and no semen should be missed. (4) Semen collection should preferably be done in the hospital and the semen should be sent for testing immediately after ejaculation. If semen is retained outside the hospital, care should be taken not to contaminate the semen, and the exact time of ejaculation should be recorded on the laboratory slip immediately after the semen is removed. The semen specimen should ideally be delivered within 30 minutes and should not take more than one hour. In winter, semen specimens should be kept warm (20-37℃) during transportation. (5) Semen collection requires a high degree of cleanliness of the container, and it is best to use a special collection container for semen specimens, so as not to contaminate the inner wall of the container.